Based on the 2000 census, over 32.8 million Hispanics in the US represent 12% of the county's total population. People of Mexican origin constitute the largest, fastest growing subgroup. They are now two-thirds of all US Hispanics, and this subgroup has grown 53% since 1990. Numerous indicators show that such alcohol-related problems as alcohol dependence and such adverse social and health consequences as cirrhosis disproportionately affect Mexican Americans- health disparities that NIAAA is committed to addressing. This research will conduct a secondary analysis of three datasets, two drawn from existing Alcohol Research Group US National Alcohol Surveys (NASs), each including large Hispanic oversamples, and the 1998 Mexican National Survey of Addictions (ENA) conducted by our collaborators at the National Institute of Psychiatry, Mexico City. Questionnaires for the ENA (n = approximately 5,712) used NAS alcohol items and scales, so assuring considerable comparability. The US surveys were conducted in 1995 (N9) as face-to-face interviews (n = 4,925; 1,589 Hispanics; 964 of Mexican descent), and in 2000 (N10+Supplement) as telephone surveys (n = 8,980; 1,132 Hispanics; est. 679 of Mexican descent) of adults 18 or older. Following preliminary analyses, we plan to pool the Mexican-descent NAS samples, limiting age range to 18-65 (pooled n = 1,542) for comparison with the ENA. Specific Aims include (1) comparing and contrasting the prevalence, predictors and correlates of heavy drinking, alcohol use disorders (AUD), and other alcohol-related problems among men and women of Mexican descent living in the two countries (US and Mexico); (2) analyzing and comparing the comorbidity of AUD and drug abuse, and AUD and depression, among these groups; (3) investigating the risk curves between key parameters of drinking pattern (volume and frequency of heavy drinking) and AUD and a range of alcohol-related health and social harms in the two Mexican- origin populations, considering the role of demographic mediators such as gender, age and (for the US) acculturation; and (4) exploring the association of alcohol treatment in relation to AUD and other alcohol-related problems, health harms, drug abuse, and depression among Mexican Americans in the US. This research accords with the NIAAA strategic action plan for addressing health disparities: using a rigorous study design, it aims to provide critically needed knowledge in detail about drinking patterns and alcohol-related consequences of a key ethnic minority population-Mexican descent Hispanic individuals-known to be at risk for alcohol dependence and other health harms from drinking. Results will inform provision of culturally appropriate health services and prevention program planning.